Related Rule
Practice Relating to Rule 15. The Principle of Precautions in Attack
Section B. Avoidance or minimization of incidental damage
Ukraine’s IHL Manual (2004) states:
When exercising command over large and small units, commands and build-ups to accomplish a mission, the commander (commanding officer) shall take all possible precautionary measures to avoid collateral damage to the civilian population and to civilian objects, or, at least, to minimize it. 
Ukraine, Manual on the Application of IHL Rules, Ministry of Defence, 11 September 2004, §